It is proposed to study the effect of various substances found in the gingival sulcus and their mechanisms on the detachment of epithelial cells from tooth surfaces. The main approach is to use an in vitro system that consists of epithelial or related cells cultured on tooth surfaces, in which various agents can be introduced and the detachment assessed quantitatively. The research objectives are as follows: 1. to develop an epithelial cell line for the studies; 2. to study the effects of various agents found in gingival sulcus, such as enzymes and endotoxin, on the detachment of cells from tooth surfaces and other relevant surfaces. 3. to study the effect of available plaque inhibitors that may be introduced in the gingival sulcus on the attachment and detachment of cells from tooth surfaces. 4. to investigate the specific mechanisms involved in cell detachment by selected agents. 5. to develop methods to study cell from cell detachment. It is hoped that our studies will identify some of the agents producing cell detachment in the gingival sulcus and clarify their mechanisms due to the comparative simplicity of the in vitro systems.